Gulf oil leak from rig explosion puts more than 400 species in potential harm's way

Times-Picayune archiveAn ibis flies through the Tiger Ridge marsh near the Caernarvon freshwater diversion. The array of life that depends on a clean Gulf of Mexico and functioning coastal estuaries can stun even those who make a living studying the area.

Advocates for preserving Louisiana's battered coastal ecosystem are sometimes accused of hyperbole in assessing its diversity and productivity. But that criticism may end after the list of species coastal scientists said are threatened by the oil spill moving toward the coast reached more than 400.

From whales and tuna to shrimp and neo-tropical songbirds, the array of life that depends on a clean Gulf of Mexico and functioning coastal estuaries can stun even those who make a living studying the area. Many of those experts are shuddering at the possible consequences of a months-long oil spill washing up on the coast.

Because of the influence of wind and tides pushing the oil northward, the area in harm's way reaches from the deep-water Gulf of Mexico across sandy beach fronts into the intricate maze of the nation's largest coastal marshes, ending only on the northernmost stretches of the freshwater wetlands dominated by cattails and cypress trees. Because of those varied environmental regimes, the area is one of the world's most productive fish and wildlife habitats.

The area under threat produces the largest total seafood landings in the lower 48 states, is a vital wintering or resting spot for more than 70 percent of the nation's waterfowl, is used by all 110 neo-tropical migratory songbirds, and produces 50 percent of the nation's wild shrimp crop, 35 percent of its blue claw crabs and 40 percent of its oysters. Ressearchers say 90 percent of all the marine species in the Gulf of Mexico depend on coastal estuaries at some point in their lives, and most of those estuaries are in Louisiana -- endangered by an oil spill that could last months.

"This is a really important time for so many species in this ecosystem, because they're just begun spawning and nesting," said Melanie Driscoll, a Audubon Society staffer who is director of bird conservation for the Louisiana Coastal Initiative.

Peak nesting, migration season

This is an especially critical time for bird life because it is peak nesting and migration times for hundreds of species. For the next two weeks the Gulf of Mexico will be the O'Hare Airport of the neo-tropical bird world with Louisiana's coast a main runway. A study by LSU reported as many as 25 million neo-tropical birds can cross the Gulf each day during this two-week peak, many of them making their first rest stops on the Louisiana a coast and barrier islands.

Shorebirds and coastal species such as pelicans and cranes are nesting on beach fronts, barrier islands and marsh rookeries, many directly in the path of the approaching slick. Mottled ducks, the state's native duck species, is in the midst of its nesting season.

Larry Reynolds, waterfowl study leader for the Department of Wildlife and Fisheries, said a large number of mottled ducks had already hatched, and hens have begun leading their broods into shallow marsh ponds.

"With the forecast we have for 20 mile per hour winds out of the south, that oil could be carried well past shorelines and deep into the marshes where those duck and chicks are," Reynolds said.

Whales, turtles, dolphins and more

Marine species in harms way include mammals such as whales and dolphins as well as turtles, all of which must surface to breath and may inhale oil. But tuna, wahoo, and billfish and other pedators will be feeding on smaller species that could be coated in the oil.

Inshore fisheries are also at a very critical al period in their life cycles. Shrimp have just begun to grow in the interior marshes, oysters have begun to reproduce, speckled trout have started their summer-long spawning season.

Oil that settles onto the bottom could be ingested by micro-organisms that are important to the larval and post-larval stages of shrimp, crabs and numerous commercially and important fish species, from trout and reds to drum, flounder and red snapper.

If the spill were just a weekend-long event, the damage could be severe but short-lived, biologists said. But with officials projecting the flow could last two months, they have grave concerns about long-term effects.

"I'm worried about mottled ducks, but if this thing lasts that long, I'm just as worried about the four to five million ducks that will be trying to spend next winter here,' said Reynolds.

"What happens when a large amount of oil gets in these freshwater areas, kills these plants and remains in the soil? What does that do for the wintering habitat for waterfowl? What does that do for anything?

"This ecosystem is just so important to so many species, it gets pretty scary."